Salient features of a parallel programmable interface-8255, Computer Engineering

Assignment Help:

Determine the salient features of a parallel programmable interface, 8255.

  • 24 I/O lines in 3 8-bit port groups - A, B, C
  • A, B can be 8-bit input or output ports
  • C can serve as 2 4-bit input or output ports
  • 3 modes of operation:

- Mode 0: A, B, C simple input or output level sensitive ports

- Mode 1: A, B input or output ports with strobe control in C

- Mode 2: A is bidirectional with control/handshake in B and C

  • A, B can only change 1 byte at a time
  • C has individual bit set/reset capability
  • Advantage is non-dedicated circuit can change port configuration with software and no 'glue logic'
  • Ports A, B, and C are used for I/O data.
  • The control register is programmed to select the operation mode of the three ports A, B, and C.
  • Mode0: simple I/O mode
  • Any of the ports A, B, CL and CU can be programmed as input or output.
  • No control of individual bits (all bits are out or all bits are in)
  • Mode 1: Ports A and B can be used as input or output ports with handshaking.
  • Mode2: Port A can be used as bidirectional I/O port with handshaking

 


Related Discussions:- Salient features of a parallel programmable interface-8255

What is building and running mpi programs, Q. What is Building and Running ...

Q. What is Building and Running MPI Programs? MPI parallel programs are written using conventional languages such as FORTRAN and C. One or more header files like 'mpi.h' may be

What is test requirements, Test requirements are definite in the Requiremen...

Test requirements are definite in the Requirement Hierarchy in TestManager. The requirements hierarchy is a graphical outline of requirements and nested child requirements. Req

Disadvantages of unauthenticated sites, Disadvantages of unauthenticated si...

Disadvantages of unauthenticated sites All the Units entering the Intranet must be scrutinised to ensure that they are not coming from the unauthenticated sites or users. It a

Explain about shared features of olap, Shared executes most of the security...

Shared executes most of the security features into OLAP. If multiple accesses are needed admin can make essential changes. The default security level for all OLAP products is read

Define grammar of a language, Define Grammar of a language. A formal la...

Define Grammar of a language. A formal language grammar is a set of formation rules which describe that strings formed from the alphabet of a formal language are syntactically

What is demand paging, What is major difference between the Historic Unix a...

What is major difference between the Historic Unix and the new BSD release of Unix System V in terms of Memory Management? Historic Unix uses Swapping - Whole process is tran

Advantages on electronic payment system, Advantages on electronic payment s...

Advantages on electronic payment system It gives good security schemes.  Four necessary security requirements for safe e-payments are Authentication, Encryption, Integrity,

Techniques are used to increase the clock rate r, What techniques are used ...

What techniques are used to increase the clock rate R? Ans: The 2 techniques used to increase the clock rate R are: 1. We can reduce the amount of processing done in one basi

Major characteristics of a computer family, Q. Major characteristics of a c...

Q. Major characteristics of a computer family? Let us summarise the major characteristics of a computer family. These are as below: Figure: Characteristics of computer

What does the ''suppress dialog'' do, What does the 'SUPPRESS DIALOG' do? ...

What does the 'SUPPRESS DIALOG' do? Suppressing of whole screens is possible with this command.  This command permits us to perform screen processing "in the background".  Sup

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd